1. Field of the Invention
The present invention generally relates to an improved structure for a passive radiation sound box, more particularly to a sound box that is to solve problems of wind shear and low frequency control caused by reflective sound box and passive radiation sound box.
2. Description of the Prior Art
General speaker unit or amplifier unit is a complex of mass, flexible and damping applications. When a speaker unit in vibration, producing sound waves, the principle is the elasticity of the suspension system. If the speaker unit installed in a sound box, and the sound box has air, air itself has a mass, while the speaker unit generates sound pressure to compress air in the sound box, it is just like that the air marches in the sound box at the state of the pressure wave.
For achieving better effects, passive sound box and reflective sound box are designed, shown as FIGS. 1A and 1B. The closed environment has at least passive element, and a passive element 12 is disposed behind a amplifier unit 11 or on the same plane with the amplifier unit 11, and so will be able to increase the damping effect of a passive sound box 1, and buffer the sound pressure of the passive sound box 1, so that the vibrations of the passive sound box 1 is decreased and the low-frequency effect is promoted while the amplifier unit 11 is sounding.
Another reflective sound box 2 is to dispose an echo tube 22 having an open 221, shown as in FIGS. 2A and 2B. The open 221 is on the same side with the amplifier unit 21 or is not on the same side with the amplifier unit 21. So, when the amplifier monomer 21 is in vibration, the echo tube 22 can squeeze the sound pressure generated due to the air inside the sound box to enhance the sense of bass, in order to make that the reflective sound box 2 is capable of having a good resonance effect.
However, the two sound boxes, passive sound box and reflective sound box, passive components or echo tube must be in good planning and design. For reflective sound box, the sizes, positions and shapes of the opens of the sound box and the echo tube will affect the low frequency changes. If design adverse occurs when designing passive sound box or reflective sound box, the overall efficiency of the sound box and the tone orientation all have a significant impact. Hence, to design the passive sound box and the reflective sound box is particularly complicated and is effectively controlled, thus to achieve the low frequency control is limited as well. In addition to the above-mentioned drawbacks, the problem of wind shear may cause since the control is not easy, and therefore solutions to improve the problems of the passive sound box and the reflective sound box is urgently needed.
However, to design an improved structure for a passive radiation sound box in order to integrate the structural features of a passive sound box and a reflective sound box in order to solve problems of wind shear and low frequency control can be a best solution.